The drainage of rain water and condensation from the sills of windows and patio doors has long been recognized as a problem in the door and window industry. The problem is particularly acute for patio doors because the sill structure generally does not permit much latitude in designing an effective drainage system. It is well known that the sills of all sliding closure assemblies require some form of drainage to prevent rain water and/or condensation from entering the interior of a building around the movable panes. Many drainage systems designed to solve this problem have been invented. Most such drainage systems, however, require a hollow sill construction and are not adapted to the drainage of horizontally sliding closure assemblies such as patio doors which are normally constructed with a solid sill for strength and durability. The infiltration of wind driven water is also a particular problem with patio doors because it is desirable to have a sill profile that is as low and unobtrusive as possible to facilitate passage through the door with wheelchairs and the like.
Canadian Patent Application No. 2,059,505 (Heppner laid open July, 1992) discloses a sliding door sill which appears to be an aluminum extrusion having a rail for slidably supporting a movable panel of the door and a rail for supporting a fixed panel on the sill. Positioned behind the rail that supports the fixed panel is a raised platform for supporting a pile weatherstrip which prevents air and dust infiltration around the slidable panel. Provided next to the fixed panel is a drainage groove. Drainage holes are cut through the rail for supporting the fixed panel and each drainage groove is scaled with a weep seal made of a flexible rubber, such as a silicone rubber. The weep seal is provided to seal the openings against air infiltration but to yield to water pressure when water accumulates in the drainage groove. It is not clear from the disclosure of this invention, but it appears that the weep seal extends along the entire bottom edge of the fixed panel.
U.S. Pat. No. 5,067,279 (Rolscreen Company, Nov. 26, 1991) describes a door threshold for an inwardly swinging door which comprises a two-part extrusion having an interior section and an exterior section. The interior section includes a plurality of drain holes intended to drain water entering past the door. Each drain hole is provided with a silicone rubber check valve which is designed to permit water to drain outwardly but to prevent air from infiltrating from the outside. The check valve is designed to open when enough water accumulates to provide adequate pressure to open the valve. Wind pressure is said to close the valve so that water is not blown inwardly across the sill. The valve is an elongated triangular shape which is mounted inside the threshold, thus requiring the two-part construction of the extruded threshold.
British Patent No. 1,537,347 (Clive Investments Pty. Limited, Dec. 29, 1978) relates to an extruded aluminum construction for door or window sills of the horizontally sliding type. The sill includes integral hinges on either side which support hinged flaps that are intended to permit water to drain from the sill while inhibiting the intrusion of air. The hinged flaps extend the full length of the inner and outer sides of the sill. It appears that in a normal condition, the flaps are spaced away from the sill and would permit air intrusion. Only with adequate air pressure would the flaps close against stops provided in the sill. Each side of the sill forms a support rail for a sliding panel. It is not disclosed how fixed panels are secured to the rail.
U.S. Pat. No. 4,003,171 (Mitchell, Jan. 18, 1977) describes a hydrostatic water discharge valve for an extruded aluminum window sill which is assembled from two or more extruded components. The hydrostatic discharge valve is positioned inside the sill to cover a drainage orifice through a partition in the sill. The valve includes a flap which is hingedly connected to the sill and a horizontal actuating vane which extends into the inner chamber of the sill below a weep opening. The actuating vane is designed to exert opening pressure on the discharge valve when water seeps through the weep opening and drips onto the actuating vane. This arrangement is useful only with two part hollow extrusions because the discharge valve has to be hingedly suspended from an inner partition of the window sill.
U.S. Pat. No. 3,845,599 (Comalco Limited, Nov. 5, 1974) discloses a drain valve assembly for an extruded two-part window sill which is designed to permit water to drain to an outside wall, to inhibit wind-blown water from migrating inwardly across the sill. The drain valve comprises a box-shaped structure having a partition wall which divides the structure into two chambers open at the top. A cylindrical float is positioned in the rear chamber under a drain opening, Water draining into the window sill enters the drain opening and flows over the float and the partition. In calm conditions, the water flows outwardly through a drain opening and an outer surface of the window sill. If high winds force water through the drain opening, the air pressure raises the water level in the float chamber and the float rises to block the drain opening, inhibiting water migration back across the sill. Again, this particular valve design can only be used in two-part hollow window sills since the sill must be in a disassembled condition in order to install the drain valve body.
It is an object of the present invention to provide a drainage system for horizontally sliding closure assemblies such as patio doors which permits the drainage of water from the interior of the closure and minimizes the ingress of air from an exterior of a building in which the sliding closure assembly is installed.
It is a further object of the present invention to provide a drainage system for horizontally sliding closure assemblies having solid sill constructions.
It is yet a further object of the present invention to provide a drainage system for horizontally sliding closure assemblies which is inexpensive to construct and simple to install.
It is another object of the invention to provide a drainage system for horizontally sliding closure assemblies which is adapted to be retrofitted to an installed horizontally sliding closure assembly.